8/20:Washington Redskins running backs Rob Kelley and Samaje Perine saw their fantasy value potentially take a hit on Monday as the team signed free-agent RB Adrian Peterson on Monday. The 33-year-old veteran will compete for the starting job, and has two preseason games to get acclimated to the offense. Kelley's familiarity with the system will likely mean he sees plenty of early-down work, at least initially. Perine is nursing an ankle injury, so it's unclear when he'll be able to return, but he too should mix in. Reserve Byron Marshall (ankle) is also on the shelf, and his role is up in the air now. Chris Thompson is still in the plan, too, and will likely reprise his role as the pass-catcher out of the backfield. The move potentially pushes Kapri Bibbs to the curb, as he might be on the roster bubble if the team likes what it sees from Peterson.--Daniel E. Dobish - RotoballerSource: Redskins.com - Jake Kring-Schreifels